JPH0794868B2 - Shift mechanism of manual gear transmission - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manual gear transmission having forward five speeds provided with a synchronizing device and reverse gears not provided with a synchronizing device, and more particularly to smoothly performing a reverse shift. To obtain a shift mechanism.

(Prior Art) In general, a reverse shift for reverse travel is performed when the vehicle is stopped, and therefore a synchronizer is often not provided for the reverse shift. However, when the clutch is cut to shift the shift lever to neutral and the vehicle is stopped, the drive shaft from the clutch to the transmission and the gears mounted on the drive shaft, the counter shaft that constantly engages with the drive shaft and rotates together, and the counter shaft mounted on it Gears continue to rotate due to inertia. Due to the relatively large moment of inertia of these members and the remarkable progress of bearing technology including the improvement of lubricant, the rotation due to inertia is not damped at all, and the shift is not performed smoothly when performing reverse shift. Gear noise is often generated. In order to solve this problem, the applicant of the present invention, in JP-A-57-137747, utilizes one of the synchronizers at forward speed, and through the friction engagement surface thereof, from the transmission output shaft to be stopped to the above-mentioned. It has been disclosed that a braking torque is applied to a member that is still rotating to damp the rotation of the member. However, in the present invention, since it is premised that the synchronizer used for braking has the same shift direction as the reverse forklift, the link mechanism between the reverse forklift and the forkshift for synchronizer has various structural features. In a constrained and conventional five forward gearbox construction, it has been difficult to utilize the fifth speed synchronizer, which is most preferred for use in braking.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to improve the shift mechanism of JP-A-57-137747, further improve the braking action, and make the link mechanism more compact. There is.

(Means for Solving Problems) Reference numerals used in one embodiment of the present invention to be described later are added for reference, and the present invention provides a plurality of forward speeds equipped with a synchronizer. And a shift mechanism of a manual gear transmission having a marching speed not provided with a synchronizing device, the reverse fork shaft 7, and one synchronizing device having an operating direction opposite to an operating direction of the reverse fork shaft 7. When the reverse shift is performed by interlocking the fork shaft 11 with the fork shaft 11, the one synchronizing device is frictionally engaged to damp the rotation of the counter shaft 4. Machine case 1
A shaft 16 fixed to the shaft 16 and a lever device 13 rotatably provided around the shaft 16. One end of one arm of the lever device 13 has a groove provided on the reverse shift fork 9.
The fork shaft 11 of the one synchronizer is provided with a groove 12 having a predetermined length in the axial direction, and is engaged with the end 10 of the other arm of the lever device 1 without any play. The part is engaged with the groove 12 having the predetermined length, leaving a play behind in the operation direction of the fork shaft 11 of the one synchronizer, so that the reverse stage is selected. When this happens, the end of the other arm of the lever device 13 transmits a force to the fork shaft 11 of the one synchronizer to operate the synchronizer, and at the same time, the provision of the one synchronizer is performed. When the selected gear is selected, the fork shaft 11 of the synchronizing device does not operate the lever device 13, and the length of the arm that engages with the reverse shift fork 9 is one of the above. Length of the arm that engages with the fork shaft 11 of the synchronizer Remote, characterized in that short.

(Operation) In the present invention, the reverse fork shaft 7 and the one fork shaft 11 of the synchronizing device move in opposite directions to each other, and the length of the arm of the lever device 13 that engages with the reverse shift fork 9 is By making the arm length of the lever device 13 engaged with the fork shaft 11 of one synchronizing device shorter than the arm length of the lever device 13, the reverse fork shaft 7
Fork shaft of one synchronizer than the moving speed of 11
The moving speed of the synchronous movement device becomes faster, which causes the friction engagement of the synchronizer to start earlier and the friction engagement area to be expanded.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a reverse gear 3 fixed to a transmission output shaft 2 and a counter reverse gear 5 fixed to a counter shaft 4 are operated by moving a reverse idler gear 6 slidable in the front-rear direction. By connecting to
The transmission will be in reverse. The idler gear 6 is moved back and forth by a reverse shift fork 9 fixed to a reverse shift fork shaft 7 which is shifted back and forth by a shift lever (not shown), and is engaged or disengaged with the reverse gear 3. .

5th gear shift dedicated fork Shaft 11 is Shaft 7
Like the above, the shift lever shifts back and forth, but its operating direction is opposite to the operating direction of the shaft 7. Other than this, there are forks for first and second speeds, and forks for third and fourth speeds, but not shown.

Reverse shift fork 9 and 5th speed fork shift
A lever device included in the link device and rotatably mounted on a shaft 16 fixed to the transmission case 1, that is, a reversing lever 13, is provided between the reverse gear 11 and the reverse shift fork 9. When the reverse shift is performed, the movement of the fifth speed fork shaft 11, which will be described later, is caused accordingly. As shown in FIGS. 1, 2, and 3, the pin 14 provided at one end of the reversing lever 13 engages with the groove 10 provided in the reverse shift fork 9 with almost no play. The pin 15 provided at the other end of the reversing lever 13 has a third
As shown in the drawing, a groove 12 provided in the fifth speed fork shaft 11 so as to have a predetermined length in the axial direction,
When viewed from the operating direction of the high speed fork shaft 11, the pin 15 is engaged with the rear side (that is, the left side in FIG. 3) leaving a play gap, and when the shift lever is in the neutral position.
Borders 12 front sides. Therefore, in the reverse shift, when the pin 15 moves to the right, the force is immediately transmitted from the pin 15 to the fork shaft 11, but on the contrary, when the fork shaft 11 is moved to the right to shift to the fifth forward speed, Fork Shaft 11 has no effect on Pin 15.

Further, when any one of the four fork shafts is selectively operated by the shift lever, all of the other fork shafts are held at substantially the neutral position, so that the third fork shaft
An interlock mechanism, a part of which is shown on the right side of the figure, is provided. That is, the reverse fork shaft 7 and the fifth speed fork shaft 11 are provided with recesses at opposite positions, and the pin 20 that slides in the hole formed in the case 1 at a right angle to the axial direction therebetween. Is provided. When both shafts 7, 11 are in their neutral position, both pin 20 and both shafts 7, 11 are free to move to some extent. But if a shaft is forced to shift
The 20 is pressed into the recess of the other shaft, holding the other shaft in approximately its neutral position.
The curve ABCFD in FIG. 4 shows the limit at which the displacement of the fork shaft 11 is limited according to the position of the reverse fork shaft 7.

As shown in FIG. 1, the reversing lever 13 is slidably mounted on a shaft 16 and is pressed by a coil spring 17 against an E ring 18 fixed to the shaft 16. As shown in FIG. 2, the distance b between the pin 15 and the shaft 16 is set larger than the distance a between the pin 14 and the shaft 16.

Next, the movement of the above-mentioned members when the reverse shift is performed will be described. When the shift of the reverse fork shaft 7 is started, the groove 10 provided on the reverse shift fork 9 pushes the pin 14 of the reversing lever 13 in FIG.
The reversing lever 13 is rotated about the axis 16 to move the pin 15 in the opposite direction to the moving direction of the reverse forklift 7 with a moving speed of b / a times the moving speed of the reverse forklift 7. At that time, as shown in FIG. 3, the pin 15 immediately pushes the front inclined surface of the groove 12 provided in the fifth speed fork shaft 11 to move the shaft 11 to the right. That is, in FIG. 4, the shaft 11 moves along a straight line OB having a slope of b / a and reaches the point B at which the movement is stopped by the interlock device (in FIG. 3, the pin 15 and the shaft 11 are 1). It is in the position indicated by the dashed line.) During this period, frictional engagement of the synchronizer is started at point E. After reaching the point B, the pin 15 moves along the front inclined surface of the groove 12 and the coil spring 17
The shaft 11 continues to move along the side surface of the shaft 11 against the contact with the shaft 11, but the shaft 11 starts to retreat by the interlocking mechanism as shown in FIG. 4, and the frictional engagement of the synchronizer is released at the point F. , The reverse shift completion point D (in FIG. 3, the pin 15 is located at the two-dot chain line position). During this time, due to the frictional engagement of the synchronizing device from the point E to the point F, the rotational movement of the counter shaft 4 and the idler gear 6, which have continued to rotate due to inertia, is greatly attenuated, and the reverse gear 3 and the reverse idler gear 6 are Smooth engagement and reduce gear noise. The straight line OC in FIG. 4 has an inclination of 45 °, and corresponds to the case where the size of the reversing lever is a = b, and has the same operation direction as the reverse forklift as seen in the prior art. This is equivalent to using the device. As can be seen from the figure, by making the lever ratio b / a larger than 1, the friction engagement can be started earlier and the friction engagement region can be expanded.

(Effects of the Invention) As described above, in the present invention, as the synchronizing device used for braking, the synchronizing device that is operated in the direction opposite to the operation direction of the reverse forklift is selected, so that the frequency of use is reduced. It is possible to use the fifth speed synchronizer, which is relatively low and has the most synchro durability. Further, a lever device for reversing to operate the synchronizing device is provided, and the length of the arm of the lever device engaging with the fork shaft of the synchronizing device is larger than the length of the arm engaging with the reverse shift fork. Therefore, the friction engagement of the synchronizer is started earlier, the friction engagement area is expanded, and the damping effect of the counter shaft against inertial rotation is improved. Furthermore, the reversing lever for interlocking the synchronizer allows more freedom in installation location selection and space utilization compared to the interlocking mechanism provided at the tip of the shift lever in the prior art (Japanese Patent Laid-Open No. 57-137747). I was able to improve.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a shift mechanism according to the present invention as viewed in the axial direction of a transmission, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIG. 3 is FIG. III-III direction arrow view of FIG. 4, FIG. 4 is an explanatory view showing the operation of this mechanism. 1 ... transmission case, 2 ... output shaft, 3 ... reverse gear, 4 ... counter shaft, 5 ... counter reverse gear, 6 ... idler gear, 7 ... reverse fork shaft, 9 ... reverse shift fork , 10 …… Groove, 11
...... 5th speed fork shaft, 12 ...... groove, 13 ...... reversing lever, 14 ...... pin, 15 ...... pin, 16 …… axis, 17 …… coil spring, 18 …… E ring, 20 ...... pin

Claims (1)

[Claims] 1. A shift mechanism for a manual gear transmission having a plurality of forward speeds equipped with a synchronizing device and a reverse speed not equipped with a synchronizing device, said reverse fork shaft (7) and said reverse fork shaft. When performing a reverse shift by linking a fork shaft (11) of one synchronizing device having an operation direction opposite to the operation direction of (7) by a link device, the above-mentioned 1
The synchronizing devices are frictionally engaged to damp the rotation of the counter shaft (4), and the link device includes a shaft (16) fixed to the transmission case (1) and the shaft (16). A lever device (13) rotatably provided around the (16), and one arm end of the lever device (13) has a groove (10) provided on the reverse shift fork (9). Fork shaft (11) of the one synchronizer engaged without play
Is provided with a groove (12) having a predetermined length in the axial direction thereof, and the end portion of the other arm of the lever device (13) has a groove (12) having the predetermined length, and When viewed in the operating direction of the fork shaft (11) of the single synchronizing device, the fork shaft (11) is engaged with leaving a play behind, and therefore, when a reverse stage is selected, the lever device (13) is When the end portion of the other arm transmits a force to the fork shaft (11) of the one synchronizer to operate the synchronizer, and the shift stage provided with the one synchronizer is selected. The fork shaft (11) of the synchronizing device is attached to the lever device (1).
3) is not operated, and the length of the arm that engages with the reverse shift fork (9) is shorter than the length of the arm that engages with the fork shaft (11) of the one synchronizer. A shift mechanism for a manual gear transmission, which is characterized in that